the obamas have invited former president george w. bush and laura bush to travel them. the bushes have said they will. former president clinton and hillary clinton making the trip, as will former president jimmy carter, too. tonight, we learned queen elizabeth, who met mandela a number of times, has asked that her son prince charles attend in her place. and on this sunday in south africa, a day of prayer. and word from one of nelson mandela's daughters, during his final days. abc's byron pitts is there. >> reporter: this sunday was soaked in symbolism. the former township, once the epicenter of the anti-apartheid movement. grief and gratitude stretched across generations. he spoke for a nation. >> i'm here today, he fought for our freedom. if it wasn't for him, we wouldn't be here. we wouldn't be having all the things that we have. >> reporter: for nelson mandela's memorial service on tuesday, with world leaders from across the globe in attendance, it will be the largest security effort in south africa since the world cup in 2010. tonight, new details about the life he